The new study amassed data from 10 clinical trials that included a total of 77,917 people (average age: 64) who took fish oil supplements for an average of 4.4 years.
Whether the authors looked at all of those people together or broke them into subgroups (for example, diabetics, or people with prior heart disease), they could find no link between taking supplements and reducing risks.
“Studies that have showed really dramatic results [from fish oil supplements] often had small sample sizes, or employed methods that could lead to patient bias,” says Clarke, the study’s author. The new analysis only included clinical trials that involved at least 500 people.
A statement attributed to Duffy MacKay, N.D., the senior vice president of scientific and regulatory affairs at the Council for Responsible Nutrition, a group that represents the supplements industry, said that fish oil supplements should still be considered part of a heart-healthy lifestyle—but that consumers should “manage their expectations for the role that dietary supplements, such as omega-3 fatty acids, can play in reducing the risk of cardiovascular disease.”
The new findings largely affirm a report from last year by the American Heart Association (AHA), which also found almost no connection between fish oil supplements and heart disease prevention. The AHA report did find, however, that among people who had already suffered a heart attack or heart failure, fish oil supplementation was linked to a slight (10 percent) drop in the risk of dying from heart disease.
That seemingly positive glimmer shouldn’t carry too much weight, though, says David Siscovick, M.D., senior vice president for research at the New York Academy of Medicine, who led the committee behind the AHA report. It might have been the result of the way the researchers analyzed the data, he explains, or the way the questions about fish oil use and heart health were posed to patients.
“Our conclusions are basically the same,” Siscovick says. “We see no evidence to recommend prescribing fish oil supplements for heart health.”